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At least 73 records · Page 4Linked to original sources
PubMed1999

Pharmacokinetic-pharmacodynamic modeling of risperidone effects on electroencephalography in healthy volunteers.

RATIONALE: CNS-active drugs produce specific electroencephalographic changes and the concentration-effect relationship of antipsychotics may be elucidated by adopting electroencephalography (EEG) as an effect measurement tool. OBJECTIVE: The purpose of the present study was to determine the concentration-effect relationship of risperidone by assessing the EEG effect after oral administrations of single dose risperidone in healthy young males. METHODS: Nine healthy male volunteers received a 1 mg single oral dose of risperidone according to a placebo controlled crossover design. Plasma levels of risperidone and its active metabolite 9-hydroxyrisperidone were measured by radioimmunoassay. Quantitative EEG parameters were obtained for each of four frequency bands through spectral EEG analysis. The difference in the absolute power in the delta frequency band for the F3 lead between risperidone and placebo was used as a drug effect parameter. For pharmacokinetic-pharmacodynamic modeling, the hypothetical effect compartment kinetically linked to plasma by a first-order process was postulated. All curve fittings were done with the non-linear curve-fitting program NONLIN. RESULTS: Our results showed that absolute powers in delta and theta frequency bands were higher for risperidone administration than for placebo at all EEG leads, and the maximum effects were detected at about 3 h after administration of the drug. The hysteresis loop was observed in the plot of plasma concentration of risperidone or sum of risperidone and 9-hydroxyrisperidone (Cp) versus EEG effect for each subject. A linear model adequately described the relationship between the effect compartment concentrations (Ce) and EEG effects, and the two limbs of hysteresis in the Cp-effect plot were collapsed in the Ce-effect plot for risperidone or risperidone plus 9-hydroxyrisperidone. CONCLUSION: The increases of absolute power for delta and theta frequency bands of EEG were induced by single oral administration of risperidone. The linear PK-PD model fit well with the relationship between effect compartment concentrations (Ce) and EEG effects of risperidone.

Administration, Oral↗
PubMed2000

Transmission imaging for registration of ictal and interictal single-photon emission tomography, magnetic resonance imaging and electroencephalography.

A method developed for registration of ictal and interictal single-photon emission tomography (SPET), magnetic resonance imaging (MRI) and electroencephalography (EEG) is described. For SPET studies, technetium-99m ethyl cysteinate dimer (ECD) was injected intravenously while the patient was monitored on video-EEG to document the ictal or interictal state. Imaging was performed using a triple-head gamma camera equipped with a transmission imaging device using a gadolinium-153 source. The images (128x128 pixels, voxel size 3.7x3.7x3.6 mm3) were reconstructed using an iterative algorithm and postfiltered with a Wiener filter. The gold-plated silver electrodes on the patient's scalp were utilized as markers for registration of the ictal and interictal SPET images, as these metallic markers were clearly seen on the transmission images. Fitting of the marker sets was based on a non-iterative least squares method. The interictal SPET image was subtracted from the ictal image after scaling. The T1-weighted MPRAGE MR images with voxel size of 1.0x1.0x1.0 mm3 were obtained with a 1.5-T scanner. For registration of MR and subtraction SPET images, the external marker set of the ictal SPET study was fitted to the surface of the head segmented from MR images. The SPET registration was tested with a phantom experiment. Registration of ictal and interictal SPET in five patient studies resulted in a 2-mm RMS residual of the marker sets. The estimated RMS error of registration in the final result combining locations of the electrodes, subtraction SPET and MR images was 3-5 mm. In conclusion, transmission imaging can be utilized for an accurate and easily implemented registration procedure for ictal and interictal SPET, MRI and EEG.

Adolescent↗
PubMed2026

Ictal electroencephalography and heart rate as treatment criteria in electroconvulsive therapy: a systematic review of the literature.

BACKGROUND: Decades before the emergence of precision medicine, psychiatrists raised the question of whether specific seizure characteristics could help optimize electroconvulsive therapy (ECT), as relationships between some of these characteristics and better outcomes were found. From 1990 onward, researchers focused on electroencephalography (EEG) and cardiovascular markers, which were broadly adopted by guidelines worldwide. However, the prognostic value of these markers is still controversial. Here, we provide a systematic summary of the studies on this topic. METHODS: We conducted a literature review on the use of ictal EEG and heart rate as outcome predictors in ECT using the PubMed, EMBASE, Cochrane and PsycINFO databases. RESULTS: Thirty-seven studies addressing more than 100 quality markers fulfilled our inclusion criteria. Single EEG markers were assigned to five categories (postictal inhibition, amplitude, coherence, regularity, and seizure duration). Heart rate and composite markers were considered separately. In contrast to single EEG markers, heart rate and composite markers could be consistently linked to better outcomes in patients with depression. Only a few studies on schizophrenia could be retrieved. CONCLUSION: Multiparametric markers outperformed single markers. Furthermore, changes in heart rate during seizures were related to better outcomes. Although clinical assessment remains the cornerstone of treatment guidance decisions, EEG and cardiac monitoring could help prevent insufficient seizures during the period preceding clinical improvement. Evidence on schizophrenia remains limited. More randomized trials are needed to analyze the role of composite markers as prognostic tools.

Humans↗
PubMed1999

Cerebral computed tomography and electroencephalography compared with neuropsychological findings in systemic lupus erythematosus.

Central nervous system involvement was evaluated in 36 patients with systemic lupus erythematosus (SLE) using cerebral computed tomography (CT), electroencephalography (EEG), and a neuropsychological test battery. The purpose was to investigate whether brain dysfunction as assessed by comprehensive neuropsychological investigation is associated with findings of routine investigation methods such as CT and EEG which are available in most hospitals. Abnormal EEG was found in 19%, and CT revealed cerebral atrophy in 47% of SLE patients. Few neuropsychological functions were affected by the presence of abnormal EEG, cerebral atrophy, or infarcts. Significant associations were found only between cortical atrophy and impairment of tactile spatial problem-solving and motor dexterity, and between cortical infarcts and motor dexterity in the dominant hand. The value of conventional EEG in assessing cerebral SLE is negligible, except for identifying epileptic activity and focal pathology. Cerebral CT has little relevance in predicting brain dysfunction as established by neuropsychological assessment in SLE, except for detecting cortical atrophy and infarcts.

Adult↗
PubMed2005

Recognition of motor imagery electroencephalography using independent component analysis and machine classifiers.

Motor imagery electroencephalography (EEG), which embodies cortical potentials during mental simulation of left or right finger lifting tasks, can be used to provide neural input signals to activate a brain computer interface (BCI). The effectiveness of such an EEG-based BCI system relies on two indispensable components: distinguishable patterns of brain signals and accurate classifiers. This work aims to extract two reliable neural features, termed contralateral and ipsilateral rebound maps, by removing artifacts from motor imagery EEG based on independent component analysis (ICA), and to employ four classifiers to investigate the efficacy of rebound maps. Results demonstrate that, with the use of ICA, recognition rates for four classifiers (fisher linear discriminant (FLD), back-propagation neural network (BP-NN), radial-basis function neural network (RBF-NN), and support vector machine (SVM)) improved significantly, from 54%, 54%, 57% and 55% to 70.5%, 75.5%, 76.5% and 77.3%, respectively. In addition, the areas under the receiver operating characteristics (ROC) curve, which assess the quality of classification over a wide range of misclassification costs, also improved from .65, .60, .62, and .64 to .74, .76, .80 and .81, respectively.

Adult↗
PubMed1996

Electroencephalography in schizophrenic patients: comparison between neuroleptic-naive state and after treatment.

Electroencephalography of 12 schizophrenic patients was recorded in a neuroleptic-naive state and after 6.2 +/- 1.1 months of treatment, when they were on medication and in partial remission. Compared with age- and sex-matched controls, the neuroleptic-naive schizophrenics had less alpha 2 power. In the medicated state, alpha 2 power and slow-wave power were reduced as compared with the neuroleptic-naive state. The reduction in alpha 2 power may occur from the early stage of the disease and progress even though the patients are medicated and clinically improved.

Adult↗
PubMed1991

Electroencephalography, evoked potentials and MRI brain scans in saturation divers. An epidemiological study.

One hundred and fifty-six air and saturation divers, mean age 33.6 (range 21-49) years, were examined. The control group consisted of 100 offshore workers and policemen with the health requirements to have a diving certificate, mean age 34.0 (range 22-48) years. The examination protocol included electroencephalography (EEG), visual evoked potentials (VEPs), brain-stem auditory evoked potentials (BAEPs) and magnetic resonance imaging (MRI) of the brain and brain-stem. Abnormal EEGs, with focal slow waves mostly in the temporal regions and sharp potentials, were found in 18% of the divers and in 5% of the controls (P = 0.003). Abnormal EEGs correlated significantly with the exposure to saturation diving (P = 0.0006) and the prevalence of decompression sickness (P = 0.0102). Alcohol consumption was negatively correlated with abnormal EEGs (P = 0.0006). Mean I-III BAEP latency was increased (P = 0.047) in the diver group. P100 VEP latency decreased with age (21-49 years). High signal intensity changes obtained by MRI were found in 33% of the divers and in 43% of the controls (P = 0.14). It is concluded that the nervous system of saturation divers is influenced by their occupation and that EEG is a useful method in the health examination of divers.

Adult↗
PubMed1996

Prognostic significance of quantitative electroencephalography in Alzheimer patients: preliminary observations.

In 31 Alzheimer outpatients followed up for a mean time of 26.4 months the hypothesis that quantitative electroencephalography (qEEG) could predict the loss of activities of daily living (ADL), the onset of incontinence, and death was tested by the Weibull proportional hazard model of 'lifereg' procedure of the Statistical Analysis System package. A central-posterior temporal region was considered in either side (power-weighted, log transformed relative values). Right delta predicted both the loss of ADL and death, whereas right theta predicted the onset of incontinence. Left values gave borderline significant results toward all end-points, whereas power-weighted mean frequency always gave borderline results. The curves calculated for predicted times may be a valid support for the clinician in attempting prognostic judgments of disease evolution.

Aged↗
PubMed1988

Effects of apomorphine in quantified electroencephalography in the frontal cortex: changes with dose and time.

The purpose of this study was to investigate the role of four doses of apomorphine (0.01, 0.05, 0.25, 1 mg/kg s.c.) on the cortical activity by a quantified electroencephalography (EEG) method recently developed in our laboratory. The EEG-effects of apomorphine were changed significantly according to the dose and the time. When initial effects were considered an opposition in the apomorphine-induced variations between low (0.01 mg/kg) and higher doses were observed. In the time course with 0.01, 0.25 and 1 mg/kg SC, EEG variations changed the direction in 6-17 Hz and diminished in the other spectral components. Qualitatively, this tardive change with 0.01 mg/kg may show a feed-back response of the dopaminergic system to the initial low dose-induced depressant effects of apomorphine. On the other hand higher doses-induced tardive EEG pattern may show a possible changed balance in the stimulated D1 and D2 receptors.

Animals↗
PubMed1995

Mapping cognitive brain function with modern high-resolution electroencephalography.

High temporal resolution is necessary to resolve the rapidly changing patterns of brain activity that underlie mental function. While electroencephalography (EEG) provides temporal resolution in the millisecond range, which would seem to make it an ideal complement to other imaging modalities, traditional EEG technology and practice provides insufficient spatial detail to identify relationships between brain electrical events and structures and functions that are visualized by magnetic resonance imaging (MRI) or positron emission tomography (PET). Recent advances overcome this problem by recording EEGs from more electrodes, by registering EEG data with anatomical information from each subject's MRI, and by correcting the distortion that is caused by volume conduction of EEG signals through the skull and scalp. Along with its ability to record how brains think when performing everyday activities in the real world, these advances make modern EEG an invaluable complement to other functional neuroimaging modalities.

Brain↗
PubMed1996

Frontal mental theta wave recorded simultaneously with magnetoencephalography and electroencephalography.

Frontal mental theta waves were recorded simultaneously with magnetoencephalography (MEG) and electroencephalography (EEG) in normal subjects. MEG analyses demonstrated that theta burst activities distribute widely in the frontal cortices of both the cerebral hemispheres during concentration on mental calculation. On the other hand, EEG showed the theta activities seemed maximal on the frontal midline part (Fz), as if they might have been generated mainly in the frontal midline cortical area.

Adult↗
PubMed1992

Diagnostic value of electroencephalography in arteriovenous malformations.

Arteriovenous malformations (AVM) are usually located superficially in the subcortical white matter, and seizures are one of the frequently seen presenting features of AVM. The diagnosis of AVM is confirmed with various neuroimaging techniques. The present study comprised six patients presenting with seizures and headaches, referred to the neurodiagnostic unit to rule out/confirm epilepsy. All patients showed epileptiform activity on electroencephalography (EEG). Further investigations, such as angiography supplemented with computed tomography (CT) showed AVM. EEG is usually not considered a valuable diagnostic tool in AVM, but our results support the finding that EEG is an extremely reliable investigative tool, and should be supplemented with angiography and CT scan for better localization of AVM.

Adult↗
PubMedDate not supplied

Serum testosterone and electroencephalography spectra in developmental male rhesus Macaca mulatta monkeys.

BACKGROUND: The main objectives in this work were to determine whether the relationship between serum testosterone concentration and electroencephalography (EEG) develop mental change observed in human males is also present in Macaca mulatta and, if so, to determine which frequency bands are involved and which regions change in pre-pubertal monkeys as a function of serum testosterone concentration. METHODS: Nine healthy monkeys were divided into three groups according to age. Serum testosterone was measured using immunoenzymatic chemiluminescent assay. EEG results were processed using Fast Fourier transform; average relative spectral power analysis was calculated and separated into delta and theta bands. RESULTS: The main findings were higher delta relative power in temporal area of the youngest group. Significant positive correlations were observed between serum testosterone levels and theta relative power across the entire scalp, and between theta relative power at frontal and temporal locations and in negative direction between delta relative power in temporal areas. Partial correlations controlling for cephalic perimeter remained significant between testosterone and total theta relative power and theta relative power in temporal areas. Partial correlations remained significant for theta relative power controlling for age at temporal locations. CONCLUSIONS: Our data show that testosterone may be a significant covariate in EEG development in Macaca mulatta males.

Age Factors↗
PubMed2006

Early electroencephalography in acute ischemic stroke: prediction of a malignant course?

OBJECTIVE: In patients with large middle cerebral artery (MCA) infarction space occupying brain edema may lead to a malignant course with up to 80% mortality under conservative treatment. As interventional treatment strategies must be started before the deterioration occurs predictors of a malignant course are necessary. PATIENTS AND METHODS: This study reports on the results of early electroencephalography (EEG) within 24h after onset of stroke in 25 patients suffering a large MCA infarct (12 patients with a malignant and 13 with a non-malignant course). EEG analysis was performed according well-established indicators for focal as well as global changes. RESULTS: Our findings indicate that the absence of delta activity and the presence of theta and fast beta frequencies within the focus predict a benign course (p < 0.05), whereas diffuse generalized slowing and slow delta activity in the ischemic hemisphere may point to a malignant course. CONCLUSION: This study shows that in patients suffering from large MCA infarction early EEG delivers useful information to select those patients who develop malignant edema.

Aged↗
PubMed2006

Seizures and adverse events during routine scalp electroencephalography: a clinical and EEG analysis of 1000 records.

OBJECTIVE: To quantify the incidence of seizures and adverse events during standard electroencephalography (EEG). METHODS: A retrospective random sample of 1000 of a total of 3391 reports of standard scalp EEG recordings during 2002 at Kings College Hospital were studied, and adverse events during standard EEG were recorded. Photic induced seizures and epileptiform activity were compared with the resting, hyperventilation and sleep EEG. RESULTS: Adverse events occurred in 131 records (13.1%), including seizures in 60 records (45 electro-clinical and 15 non-epileptic seizures). The overall incidence of electro-clinical seizures was not statistically different during the resting EEG (2.8%), sleep EEG (2%), hyperventilation EEG (2.1%) and during photic stimulation EEG (1.4%). There was a higher frequency of electro-clinical seizures during hyperventilation and sleep in those with a diagnosis of idiopathic generalised epilepsy (31.5%) and during photic stimulation in photosensitive patients (31%). The incidence of electro-clinical seizures was significantly less during activation procedures in focal epilepsies (2.6%). Activation techniques made a unique diagnostic contribution when routine resting EEG was normal or equivocal in 11% of cases. CONCLUSIONS: Adverse events occurred in 13.1% of records, and most were minor. Sixty of the adverse events were seizures. Those generated during the EEG were brief and safety precautions operated successfully. In those without a prior diagnosis, the chance of seizures is the same during both resting and activation EEG. In those patients with generalised epilepsy or photosensitivity, activation procedures have a higher rate of seizure induction. SIGNIFICANCE: This study has implications for informed consent for EEG.

Adolescent↗
PubMed2006

Amplitude integrated electroencephalography in the full-term newborn.

Amplitude-integrated electroencephalography (aEEG) is beginning to play an important role in the care of full-term infants who have neonatal encephalopathy. The three main features an aEEG provides include (1) the background pattern, showing the activity at admission to the neonatal intensive care unit and the rate of recovery during the first 24 to 48 hours after birth; (2) the presence or absence of sleep-wake cycling; and (3) the presence of most electrographic discharges.

Brain↗
PubMed2006

Continuous electroencephalography monitoring of the preterm infant.

Continuous electroencephalography (EEG) monitoring provides clinically relevant information in preterm infants. Acute changes during development of intraventricular hemorrhage and white matter injury are associated with EEG and amplitude-integrated EEG (aEEG) deterioration. The early EEG background is also correlated with outcome in preterm infants, although other problems associated with prematurity may influence the long-term prognosis. The limitations of EEG monitoring should be well-understood by users and the continuous EEG monitor should be used as a complement to the standard EEG.

Brain Diseases↗
PubMed2006

Training neonatal staff in recording and reporting continuous electroencephalography.

Continuous electroencephalography can contribute useful information to clinical decision-making in neonatal care. Equipment is now reliable and user-friendly enough that its use can be taught to medical and nursing staff so that a 24-hour capability is achieved. It is possible to teach neonatologists, in a 1-day course, background knowledge on EEG and amplitude-integrated EEG (aEEG), recognition of aEEG patterns that have clinical significance, recognition of seizures using aEEG and "raw" EEG, the essentials of electrode placement for aEEG, and interpretation of findings in the clinical context. This must be followed up by background reading, frequent peer-review sessions on EEG recordings, and a reliable system for storing and access, as well as willingness to consult experienced operators elsewhere.

Education, Medical, Continuing↗